Triple Layer Research Articles

Formation of the incommensurate Si(111)-∼5.4 × ∼5.4-In surface

We find that the 5 × 5 reconstruction can form only by indium deposition on the ‘rect’ structure of the Si(111)-7×3-In surface in a step-flow-like growth manner, which was previously known to form by deposition of the 7,7,8,8-tetracyanoquinodimethane (TCNQ) molecules on the 7×3-rect surface. The 5 × 5 reconstruction is found to be an incommensurate structure that should be expressed as ∼5.4 × ∼5.4, instead of the 5 × 5. The ∼5.4 × ∼5.4 surface consists of a triple indium layer with about 3.1 ML coverage, and has a strong insulating character, in contrast to the metallic electronic states on the 7×3-rect surface. The ∼5.4 × ∼5.4 surface is considered to be rather unstable at RT.

A novel graded approach for improving the efficiency of Lead-Free perovskite solar cells

Methylammonium tin iodide (MASnI3) is the most commonly used lead-free perovskite absorber material to resolve the issues related to toxic lead (Pb)-based MAPbI3 perovskite. However, conversion efficiency for MASnI3-based perovskite solar cells (PSCs) are still struggling to compete with lead-based PSCs. Therefore, this study provides a roadmap to achieving 22.3 % conversion efficiency for MASnI3-based PSCs through extensive device modeling. The work utilizes the graded active layer approach to attain higher excitons inside the active layer. The opto-electrical model's combined effort is considered an excellent light trapping mechanism by matching precise bandgaps 1.3 eV/1.3 eV for a higher generation of excitons. Detailed investigation and optimization of single, double, and triple graded perovskite absorber layer (PAL) have been done in terms of absorber layer thickness, temperature, back contact materials, and bulk defect density to achieve a conversion efficiency of 22.3 %. Results revealed that double-graded perovskite outperforms compared to single and triple-graded material and delivered excellent photovoltaic (PV) parameters such as short circuit current density (JSC) of 33.51 mAcm−2, open-circuit voltage (VOC) of 875 mV and fill factor (FF) of 75.93 %. This paper provides a smooth pathway for futuristic development and further optimization of the device lead-free MASnI3-based PSCs.

Mathematical Analysis of Transverse Displacement of Laminated Beam with Thermal Load

Objectives: This research emphasis on developing solution of transverse displacement for simply supported beam subjected to thermal load using hyperbolic shear deformation theory (HYSDT). Moreover, the significant transverse displacement analysis of single, three-layer orthotropic symmetric laminated beams exposed to sinusoidal thermal loads was taken under consideration with the aim to achieve exact solution for the above condition. Methodology: In this solution, we have used hyperbolic function in reference to thickness co-ordinate by considering shear deformation theory. The governing equations, boundary conditions were developed using principle of virtual work and thus exhibiting solution by Navier’s theory. Findin g: It is observed that by considering single, triple layer transverse displacement for simply supported beam subjected to thermal loading as well as applying hyperbolic shear deformation theory (HYSDT) has predicted transverse displacement of 0.269, 0.210 and 0.562 for ply angles such as 00, 900, 00/900/00 respectively with aspect ratio 20. In accordance with this we observed uniformity among the predicted values. Novelty: In this research we have introduced an advance function such as hyperbolic shear deformation theories (HYSDT) and transverse displacement for variable lengths and thickness of the beam was calculated by using MATLAB coding. Thus, achieving precise solution. Keywords: Sinusoidal load; hyperbolic shear deformation theory; governing differential equations; MATLAB coding; thermal load

Efficiency enhancement of triple absorber layer perovskite solar cells with the best materials for electron and hole transport layers: numerical study

In this paper, a novel perovskite solar cell (PSC) with a triple absorber layer is numerically simulated using Solar Cell Capacitance One-Dimensional software. The initial simulation of the structure (FTO/TiO2/CsSnI3/CsSnGeI3/Cs3Sb2Br9/spiro-OMeTAD/Au) reveals that by combining cesium tin triiodide (CsSnI3), cesium tin-germanium triiodide (CsSnGeI3) and cesium antimony bromide (Cs3Sb2Br9) as triple absorber layer, we obtain a higher efficiency (31.81%) than the single (CsSnI3), and double (CsSnI3/CsSnGeI3) layer structures, whose efficiencies are 12.87% and 29.41%, respectively. Then, to optimize the proposed structure, different parameters like; thicknesses of the triple absorber layer, different materials of electron transport layer (ETL) and hole transport layer (HTL), thicknesses of ETL and HTL, as well as the operating temperature have been investigated. The optimized structure (0.4/0.1/0.1 µm of CsSnI3/CsSnGeI3/Cs3Sb2Br9 as triple absorber layer; 0.1 µm of tungsten trioxide WO3 as ETL and 0.35 µm of copper(I) oxide Cu2O as HTL, as well as an optimum temperature of 300 K) shows a remarkable photovoltaic parameters i.e. J SC = 32.640 774 mA cm−2, V OC= 1.2442 V, FF = 89.17% and η = 36.21% (which corresponds to an improvement of 4.4% compared to the initial proposed structure (31.81%)). This study’s simulation results open a better route toward fabricating highly efficient PSCs.

Photoflash and laser ignition of Al/PVDF films and additively manufactured igniters for solid propellant

Solid propellants are employed in a range of applications from the inflation of airbags to propulsion systems for rockets. The ignition of solid propellants must be carefully controlled and modified on a per-use basis due the specific ignition requirements of each application. Using tailored photoreactive materials as a source of ignition for solid propellants, or other energetic materials, could reduce the added weight and risk of traditional initiators and result in safer, more effective solid rocket motor ignition systems. This study demonstrates the tunability of the ignition delay and propagation properties of optically-sensitive, nearly full density reactive aluminum/polyvinylidene fluoride (Al/PVDF) films and additively manufactured igniters. A single printed layer of pure nano-aluminum (nAl) at ideal stoichiometry in PVDF was found to flash ignite, but frequently yielded delayed transitions in steady propagation from the igniter to the propellant. To improve the continuity and steadiness of the transition, fuel particle size, igniter thickness, and a combination of layers of nAl and micron-sized aluminum (μAl) were investigated. In printed igniters with layers of μAl, only a single layer of nAl was needed to flash ignite the material and propagate to the layers of μAl without delay. For igniters cast onto strands of ammonium perchlorate composite propellant, continuous ignition was achieved with a single layer of nAl printed atop a triple layer of μAl for the flash-activated igniters and a single layer of nAl printed atop a single and triple layer of μAl for laser-driven igniters. The nAl/PVDF layer enabled good flash or laser ignition sensitivity, while the μAl/PVDF produced more sustained heat transfer to produce a reliable ignition process.

Security-Enabled Retransmission and Energy Conservation Architecture With Cluster-Based Multipath Routing in Heterogeneous Wireless Networks

The primary requirements of a heterogeneous wireless network topology, adaptive and smart resource allocation to users, protocols for routing and lifetime enhancement, access to the network with security and appropriate network selections. Routing algorithms deliberate on the performance of the network to evenly distribute load and thus enhance the lifespan of individual nodes, clustering algorithm decides on allowing the right nodes into the network for enhanced security feature, and finally the ability to analyse, predict the context of individual nodes/sensors in the network. Architecture of the proposed network includes the parameters such as decision making ability to sustain the clusters, decision on members of the clusters until the communication process is completed, local network abilities and disabilities, price, preferences of individuals, terminal and access points of the service providers. Network lifetime of the entire network is observed to be enhanced up to 91% with triple layer architecture.

A Stretchable and Tough Small-Scale Magnetic Actuator for Biomedical Applications

A stretchable, tough, small-scale magnetic actuator capable of multimodal locomotion under magnetic fields is proposed. The actuator consists of a silicone elastomer (Ecoflex 00-10) embedded with neodymium-iron-boron (NdFeB) particles and coated with a poly(2-methacryloyloxyethyl phosphorylcholine) (PMPC) triple network hydrogel layer. The hydrogel layer is biocompatible and decreases the surface friction of the actuator. Mechanically, the actuator is highly stretchable, tough, and fatigue-resistant. The application of the actuator in drug delivery is demonstrated.

A Biosensor Based on Bound States in the Continuum and Fano Resonances in a Solid–Liquid–Solid Triple Layer

We propose a simple solid–liquid–solid triple layer biosensor platform based on bound states in the continuum (BICs) and Fano resonances to detect the acoustic properties of liquids and apply the method to a mixture of water and albumin with various concentrations. The solid–liquid–solid triple layer is composed of an epoxy as a solid layer and an albumin–water mixture as a liquid layer, and the entire system is immersed in water. In this work, we show that the structure exhibits a high sensitivity (S), quality factor (Q), and figure of merit (FOM) with a better detection limit (DL) in the vicinity of the BICs where the transmission spectra exhibit Fano resonances. The Fano resonances shift towards high frequencies as the concentration increases. The detection limit can reach very small values for a small albumin concentration (4.7%). In addition, for a given concentration and layer thickness of the sensing material, we show the effect of the incidence angle on the efficiency of the sensor in terms of the sensitivity and quality factor. The proposed structure can be designed from low-cost material and can be used as a sensor to detect different types of liquids and gases as well.

Role of ozone addition on premixed hydrogen/oxygen flames: Multi-zone structure and multi-regime dynamics

This study investigates the effects of additive ozone on the ignition and propagation of premixed hydrogen/oxygen flames, with emphasis on the steady flame structure and the transient ignition and propagation behaviors due to the ozone chemistry and transport. We first simulate the 1D freely-propagating hydrogen/oxygen flames with and without additive ozone, and demonstrate that the ozone-enhanced flame has a triple reaction layer structure, which consists of an ozone reaction layer, with substantial heat release, situated within the entire preheat zone. This spatially non-monotonic nature of the heat release rate and the associated temperature gradient then implies that the conventional definition of the flame thickness, δ=(Tb-Tu)/(dT/dx)max, is incapable and indeed inappropriate to characterize the ozone-enhanced flame thickness. The multi-zone flame structure then leads to multi-regime flame dynamics, with the structure of a single ozone-sustained branch followed by decoupled and coupled double branches controlled by ozone and oxygen reactions respectively. The critical radius and the transition regime of the ozone branch are captured over a wide range of equivalence ratios, which are induced by the large Lewis number of ozone and the interaction between the ozone and oxygen branches. As such, the regime diagram of the flame propagation speed versus the stretch rate respectively corresponds to three to six regimes in the ozone branch, and zero to five regimes in the oxygen branch under ultra-(fuel)-lean, fuel-lean, stoichiometric and fuel-rich conditions. The modification of the minimum ignition energy in ozone–assisted flames is also noted.

Fermi surface chirality induced in a TaSe2 monosheet formed by a Ta/Bi2Se3 interface reaction.

Spin-momentum locking in topological insulators and materials with Rashba-type interactions is an extremely attractive feature for novel spintronic devices and is therefore under intense investigation. Significant efforts are underway to identify new material systems with spin-momentum locking, but also to create heterostructures with new spintronic functionalities. In the present study we address both subjects and investigate a van der Waals-type heterostructure consisting of the topological insulator Bi2Se3 and a single Se-Ta-Se triple-layer (TL) of H-type TaSe2 grown by a method which exploits an interface reaction between the adsorbed metal and selenium. We then show, using surface x-ray diffraction, that the symmetry of the TaSe2-like TL is reduced from D3h to C3v resulting from a vertical atomic shift of the tantalum atom. Spin- and momentum-resolved photoemission indicates that, owing to the symmetry lowering, the states at the Fermi surface acquire an in-plane spin component forming a surface contour with a helical Rashba-like spin texture, which is coupled to the Dirac cone of the substrate. Our approach provides a route to realize chiral two-dimensional electron systems via interface engineering in van der Waals epitaxy that do not exist in the corresponding bulk materials.

Adsorption behavior of chromium in an aqueous suspension of δ-alumina in absence and in presence of humic substances

Abstract The radioisotope Cr-51 was exploited for studying the chromium adsorption behavior in aqueous media of alumina in aqueous media. Where, it represents 1.8% by weight and exists in earth’s crust in different forms. Factors affecting this adsorption behavior are pH, amount of alumina and humic acid presence. In case of pH adsorption curves, three different areas under peak can be described based on pH changes which lead to the formation of different species too. The first area is the maximum constant adsorption at pH, range 1–3, the second one is adsorption decreasing with increasing pH through pH range 4–7 and the third one is step-down adsorption at higher pH range. The increasing amount of alumina leads to increase in the percent adsorption, where 10 and 2 g/l alumina were found to have 100% while in case of 0.2 g/l it is 80%. The presence of humic acid decreases the adsorption of chromate with increasing pH to be 30% comparing to 80% in case of 0.2 g/l alumna at pH 2. This can be also indicated by adsorption capacity which is found to be 436.8 μg/g in case of 0.2 g alumina; and it decreases in presence of Humic Acid (HA) to 145.8 μg/g at same weight of alumina. Also, the equilibrium capacities are found as 54.6 μg/g for 2 g/l and 1.2 μg/g for 10 g/l. Triple layer model (TLM) was used for simulation of chromium adsorption behavior in presence of alumina with the applied conditions of study. The results showed high coincidence with the practically found data.

Structural and electrical investigation of MI2M and MI3M diodes for improved non-linear, low bias rectification

Multi-stack metal–insulator-metal diodes devices of atomic layer deposited (ALD) and sputtered Ta2O5 and Al2O3 dielectrics with Au bottom electrode are investigated comprehensively by experiment and modelling. The layer structure is inspected - and the native contact metal oxide effects are incorporated in the modelling computation - using atomic force microscopy (AFM), spectroscopic ellipsometry, and transmission electron spectroscopy (TEM). The tunnelling transport is successfully modelled using both the transfer matrix (TMM) and Wentzel-Kramers-Brillouin (WKB) methods. Parasitic currents are identified using their voltage and temperature dependence. Rectification for a triple dielectric layer device is shown to occur at a turn-on voltage as low as 170 mV with a non-linearity of 3 and an asymmetry increasing from 2.2 at the turn-on voltage to over two orders of magnitude at 1 V.

Strengthening of RC Column Using GFRP

Abstract: In construction industry, engineers try to find new, better, economical material. Today there are several new techniques observed in the industry. In recent years, the construction industry has seen an increasing demand to reinstate, rejuvenate, strengthen and upgrade existing concrete structures. This may be attributed to various causes such as environment degradation, design inadequacies, poor construction practices, lack of regular maintenance, revision of codes of practice, increase in loads and seismic conditions etc. One of the technique used is the wrapping of damaged and newly constructed columns with GFRP. As GFRP has the properties like high strength, light weight, resistance towards chemicals and salt water, it can be moulded into complex shapes, requires low maintenance etc. The behaviour of fibre reinforced polymer on different shapes of column has been extensively studied, but much less is known about concrete in FRP confined damaged columns. In this project a total of 21 columns are casted, out of which 3 columns are conventional columns, 9 columns are damaged & 9 are newly constructed columns. The columns are wrapped with single, double and triple layer of GFRP. An average increase of 33.21% is observed in damaged single layer wrapped GFRP column and 51.64% in damaged double layer wrapped GFRP column and 62% in damaged triple layer wrapped GFRP column. Similarly, 46.93% of increase in newly constructed single layer wrapped GFRP column and 72.56% of increase in newly constructed double layer wrapped GFRP column and 90.23% of increase in newly constructed triple layer wrapped GFRP column. Keywords: GFRP, damaged column, newly constructed column.

PENGUATAN DAN PENGEMBANGAN MODEL BISNIS BERKELANJUTAN GLEN CHOCO: PENDEKATAN TRIPLE LAYER BUSINESS MODEL CANVAS

Cocoa plants are a leading plantation commodity that entirely exists in Indonesia. One of which is the highest production of Edel Cocoa in 2019 located at PTPN XII Kendenglembu, which has cocoa processing industry, namely Doesoen Kakao, and has great potential in improving the economy and social aspects. However, the weakness is using aluminum foil packaging, which is considered less environmentally friendly. The purpose of this study is to find out the mapping of the sustainable business model of the “Glen Choco” using TLBMC (Triple Layer Business Model Canvas) and decision using PMIA (Plus Minus Implication Analysis). The research method uses descriptive and analytic methods. The results show: 1) The results on TLBMC at the economic layer describe all elements, the environmental layer can’t describe the End of Life because the packaging isn’t environmentally friendly, the social layer can’t describe the Social Impact because it has no impact poor social society, 2) Decision on PMIA is the economic layer has a high score of 109 to strengthen the business model. The environmental layer has the lowest score of 70 to develop a business model, and the social layer has a high score of 96 to strengthen the business models.

Modeling and numerical simulation of high efficiency perovskite solar cell with three active layers

Recently, organic–inorganic metal halide perovskites, due to their promising optical properties, are widely used in solar cell applications yielding power conversion efficiencies (PCE) above 21%. In this study, using solar cell capacitance one-dimensional tool (SCAPS-1D), we have numerically simulated a novel solar cell consisting of three perovskite absorbers (MASnI3, MAPbI3 and FAMASnGeI3) as the active layer and achieved power conversion efficiency of 30.77%. We have also compared the performance of the proposed triple active layer perovskite solar cell (PSC) with single (MAPbI3) and double (MASnI3, MAPbI3) active layer PSCs and observed that the triple active layer PSC outperforms the single and double layer structures. Moreover, changing hole transport layer (HTL), it is found that inorganic Cu2O can be a suitable substitute for expensive prevalent organic Spiro-OMeTAD as HTL of our PSC and enhances the device PCE to 31.04%. In addition, by increasing the first absorber layer’s (MASnI3) thickness, while maintaining the total active layer thickness constant, a high PCE of 31.44% for triple active layer PSC is achieved. Furthermore, it is shown that materials with work functions more than 4.4 eV are not appropriate to be used as front contact of this structure. Finally, our simulations indicate that increase of defect density in absorber layers and working temperature of the cell monotonically degrade the efficiency of the device. We believe that the proposed triple active layer PSC can open a new route for realization of highly efficient PSCs.

Design and Simulation of Triple Layer Antireflection Coating for Silicon Solar Cells

In present work an attempt has been made to investigate the effect of triple layer anti-reflection coating (TLARC) on the surface of silicon cell theoretically. In this regard, MgF2, Si3N4, and TiO2 have been used to design anti-reflection coatings (ARC). Reflection spectra for single double and triple layer ARCs have been evaluated numerically using transfer matrix method (TMM). Numerically calculated reflection spectra for single, double, and triple layer anti-reflection coatings further used in PC1D simulator to study the performance of silicon solar cell. Result shows reduction in reflectance of silicon solar cell down to less than 3% in the wavelength range 400 – 1200 nm with conversion efficiency 21.6% for TLARC (MgF2/Si3N4/TiO2).

Better color distribution uniformity and higher luminous intensity for LED by using a three-layered remote phosphor structure

Abstract Angular color distribution uniformity has been one of the most relevant properties in the development of white light-emitting diodes (WLEDs), since color consistency and uniformity are crucial factors in quality evaluation of a WLED. Here, particularly considering the need to overcome the poor chromaticity usually associated with WLED, we introduce a new design for the remote-phosphor package, namely a three-layered or triple-layer (TL) phosphor structure. Using three phosphor layers in packaging a WLED can result in higher color quality and luminous efficacy, compared to the double-layer (DL) configuration. In the present study, the results of using three remote phosphor layers indicate that although the structure using three layers has a lower color rendering index, the color quality scale is better than that available from the package with two layers. Additionally, the color-deviation values in the TL structure are smaller than in the dual-layer one, especially at high color temperatures (7,700 K and 8,500 K). Besides, in comparison with the DL model, the TL package increases the luminous flux by 1.4%–2%. Therefore, the TL remote phosphor structure possesses the greatest potential in enhancing the WLED quality.

High density hexagonal MTJ array with 72 nm pitch and 30 nm CD by using advanced DRAM patterning solution and ion beam etch

A hexagonal honeycomb magnetic tunneling junction array with 72 nm pitch and 30 nm MgO critical dimension was successfully fabricated on a 1× nm dynamic random access memory platform by using a mature dynamic random access memory patterning solution and ion beam etch. To our knowledge, both pitch size and critical dimension size are the world’s smallest ones for industrial magnetic tunneling junction arrays. To obtain such a high density and small sized magnetic tunneling junction array, a cross self-aligned double patterning technique, a triple layer hard mask scheme, and an optimized ion beam etch condition were adopted. During the optimization of the ion beam etch process, the dependence of a magnetic tunneling junction pillar profile on ion beam etch parameters for a high density hexagonal magnetic tunneling junction array has also been systematically studied. The depth of oxide recess and the magnetic tunneling junction sidewall angle increased with the ion beam etch amount, while magnetic tunneling junction critical dimension and hard mask remainder thickness decreased with increasing ion beam etch amount.

Verifiable medical images for E-healthcare: A novel watermarking approach using robust bit-wise association of self-mutating offsprings of pixels

In the current difficult time of COVID-19 pandemic, social distancing is a common practice adopted by healthy and infected people all over the world. Because of this, electronic healthcare and Telemedicine are coming up a big way. One of the most vital challenges in E-healthcare or telemedicine is the authentication and secure transmission of medical images received by an expert(doctor) at a far-off location from the sender(patient). To address the critical authentication issue, this paper proposes a blind pixel-based self-embedding fragile watermarking approach that is effective enough to localize the tampered region with more than 90% accuracy. The self-embedding approach plays a significant role in fragile watermarking for detecting the tampered region at the receiver side. Most of the self-embedding-based fragile watermarking approaches available in the literature are block-based which has a high False Positive Rate(FPR). In the proposed approach, every pixel of the image dynamically generates eight self-mutating offsprings and gets associated with them tightly at bit level. After a systematic set of procedures on that offsprings with a triple layer of security, a single authentication bit is selected using 16 × 1 multiplexer for each pixel intensity of the image. That is why the proposed approach has a high imperceptibility level (more than 60 dB PSNR). Experimental results confirm the efficacy of the proposed approach in terms of imperceptibility and tamper detection rate.

Ionic Interactions at the Crude Oil-Brine-Rock Interfaces Using Different Surface Complexation Models and DLVO Theory: Application to Carbonate Wettability.

The impact of ionic association with the carbonate surface and its influence toward carbonate wettability remains unclear and is an important topic of interest in the current literature. In this work, a triple layer model (TLM) approach was used to capture the electrokinetic interactions at both calcite–brine and oil–brine interfaces. The developed TLM was assembled against measured ζ-potential values from the literature, successfully capturing the trends and closely matching the ζ-potential magnitudes. The developed TLM was compared to a diffused layer model (DLM) presented in previous works, with the DLM showing a better match to the ζ-potential values for seawater brine solutions. The ζ-potential values predicted from both surface complexation models (SCMs) were used to calculate the total interaction energy (or potential) based on the Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory. It was observed that low Mg2+ and high SO42– concentrations in modified composition brine (MCB) made the calcite–brine interface more negative. However, at the oil–brine interface, low Mg2+ made the oil–brine interface more negative but high SO42– concentrations slightly shifted the oil–brine ζ-potential toward negative. At the crude oil–brine–rock (COBR) interfaces, low Mg2+ and high SO42– concentrations in the MCB were observed to generate a greater repulsive interaction energy, which could trigger carbonate wettability alteration toward water wetness. The absolute sum of the ζ-potential at both interfaces was observed to be correlated to the total interaction potential at a 0.25 nm separating distance. Thus, an increase in the absolute sum of the ζ-potentials would generate a greater repulsive interaction potential and trigger wettability alteration. Therefore, these SCMs can be applied to design modified composition brine capable of triggering a repulsive interaction energy to alter carbonate wettability toward water wetness.